


Late Night Exercise

by Gandr



Category: Fate/Grand Order
Genre: Anal Sex, Clothed Sex, Double Penetration, F/M, Multi, Naked Male Clothed Female, Oral Sex, Shameless Smut, Threesome - F/M/M, Vaginal Sex, smut for the sake of smut
Language: English
Status: Completed
Published: 2019-10-29
Updated: 2019-10-29
Packaged: 2021-01-07 22:41:09
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,848
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21225416
Author URL: https://archiveofourown.org/users/Gandr/pseuds/Gandr
Summary: Mash and Senpai have been having physical relations for a while, and they're finally caught in the act, resulting in a surprise threeway.





	Late Night Exercise

**Author's Note:**

> As a note, the MC/Senpai in this fic is a self-insert/OC of mine named Shizuka, for those confused why it's not Fujimaru.

This had been going on for a little while.

  
The pair had had some hint of these feelings for one another; whether it was from a passing glance, a quick entwining of fingers, a gentle hug. These little acts of affection blossoming into a secret physical relationship. Whenever they were alone, it was almost certain they would be kissing, or at least cuddling close to each other. She brought him emotional comfort in her very presence, and he gave her something to keep fighting for, something to protect. Even if the relationship seemed only physical, if anyone happened to ever find out, they would know how much deeper their admiration was for each other.

This night started out no differently.

Neither was able to sleep, the moon and candlelight being the only thing illuminating the room on this particular night in Uruk. Soft, stifled moans broken the silence, soft and barely contained, followed by the sounds of cloth shuffling, a light slapping of bodies joining again and again.

It was lucky they figured out how to temporarily fake their vitals so Chaldea Command wouldn't pick up on their sudden increased heart rates. 

"Senpai..." Her voice was barely more audible than her moaning, her head turned to look back at him, mouth open as they shared a sloppy kiss, tongues caressing each other as his hand firmly groped one of her plump, soft breasts.

He moaned softly into the kiss, reveling in how warm she was, how her muscles tightened around him the deeper he thrust into her body, how warm her cheeks were every time his hips slapped against them, how sweet her voice sounded speaking his name in such a soft, needing tone. They had been at this for a little while, slow gentle thrusts into her with intermittent kissing and fondling of her chest through the black and purple leotard that made up her attire.

"You're so cute, Mash," Was his reply before pinching one of her nipples a little roughly through her clothes, eliciting a louder moan from her.

"S-Senpai, we gotta be quiet." She whined, trying to scold him but unable to find her voice to do so when she admittedly enjoyed it so much. His lips left hers for a moment before finding a new home gently kissing the warm, smooth skin of her neck, her soft moans returning. It wasn't helping her stay quiet as he seemed to purposefully push deeper inside of her with each kiss, causing her back to arch a little.

"A-Ah...!" This cry was louder than the rest as his teeth sank into her neck this time, timed with another deep thrust into her warm, slick cunt. "W-Wait, s-someone might hear - ah!" She was unable to get anything more out as he started to suck hard on her neck; knowing that any marks would vanish quickly. The pink-haired Servant's moans would only pick up in volume as he seemed to disregard to need to be quiet in favor of lavishing as much attention on his beloved partner as possible.  
Maybe this is why they didn't notice someone has poked their head into the room.

"Master?"

The masculine voice made them stop; sure, they were covered by a blanket, but the sounds they were making, how red her face was and the position of his hands made what they were doing undeniable.

The red-haired man looked at them, and then gave a knowing smile, "Hahaha, you know, Merlin jokes about you two being 'close' but I doubt he knew he was right."

Mash's face went deep red, but she didn't move and to her surprise, he was still completely rock-solid inside of her, even with the intrusion of the Lancer; how was he not becoming limp from this?

"Well, how can we keep this as just one of Merlin's jokes?" Shizuka spoke up, no hints of joking in his tone. He gave an ever so subtle thrust into Mash again, and a quick squeak, a moan passed her lips again. "Maybe some help?"

"Senpai?" It didn't take words for her to catch onto what he was implying, and it wasn't out of the question as long as he was there with her.

"Only if it's okay with Lady Mash." Leonidas stepped inside the room, and she nodded.

"Um, if I or Senpai say stop, we stop." She replied as the pair shifted; Mash whining a little when she felt him slide out of her so she could sit on her hands and knees.

"Of course." The pair of men said in unison, locking gazes with a nod as Leonidas freed himself from his attire, stepping closer to present Mash's blushing face with his already stiffened, erect cock.

"Ahaha, I heard you two when I was outside, and it seems my body still responds to the sounds of a woman's moans as it did in life," He felt a little embarrassed to admit this fact as if it was rude even though they were the ones making noise. The Shielder just shook her head and smiled sheepishly, shifting her weight to reach up and stroke it.

Her eyes widened a bit; it was so thick in her hand, would it even fit?

  
"It's okay, Senpai is the one who kept making me moan too loudly," She replied, looking back at him with a small, almost devilish smirk before taking the other man's shaft into her mouth, eyes closing as she slid it past her lips, nearly taking the entire thing inside. Her eyes widened in surprise, a sudden moan trapped in her throat. A wave of pleasure washed over her as she felt Shizuka suddenly enter her from behind once more; this time being more forceful in comparison with how slow and gentle they had to be moments before.  
Leonidas put his hands on her head, gently thrusting into her mouth at the same time, the sounds of her muffled moaning combining with the feeling of her warm, wet tongue on his cock making her almost irresistible. The pair continued, her moans picking up in volume as her Senpai pushed deeper into her; her fluids running down her legs as her body shook, fingers and toes curling as her climax rippled through her. Her moans of pleasure only continued to reverberate around the thick cock being slid in and out of her mouth as her Master continued to thrust into her, letting the nearly overwhelming waves of pleasure flood her mind.

  
"Sorry, Lady Mash," Her eyes widened again when she felt something suddenly flowing into her mouth, down her throat, and she realized the Lancer had climaxed as well; spraying his thick, hot load of cum down her throat. She closed her eyes and swallowed, gasping for a quick breath when he pulled out of her.

  
"I-It's fine, Leonidas." She moaned, looking back, "Senpai, what would you like to do?"

  
"Well," he replied, "We can keep going if you'd like. I know Leonidas has more than one shot in him."

  
His response was met with a chuckle, and the other man was indeed still ready to go; not even a hint of slowing down. Shizuka slid out of her again, laying on his back to allow her to slide herself on top of him. After a quick drink of water, both to wash her mouth out and because she was indeed working quite hard, she pulled her leotard aside as she slid onto her beloved Master's cock, her cunt wrapping around him tightly as she moaned. it was almost too much and she wondered if she would orgasm again just from this, but she endured.  
She leaned in, locking her lips with his, feeling him reach down to spread her cheeks, silently enticing Lancer. Without missing a beat, he made sure to use a liberal amount of oil to lube himself up.

  
"Ready?" They both seemed to ask in unison, and she nodded, suddenly hanging her head in a long moan that seemed to be a mix of pleasure and slight pain as he slowly entered her ass. Her Master's hands cupped her cheeks, kissing her lips gently as she moaned, the two men now completely sheathed inside of her. One at a time, in an alternating pattern they began to thrust into her as she tried to hold herself up in spite of the sheer overload of having these two men inside of her. She gave a small cry of surprise when she felt her breasts suddenly hang free and realized Shizuka had pulled her cleavage window down.

  
"S-S-Senpai," She moaned, face buried in the pillow next to his head, bare breasts pressed onto his chest, "Y-You both f-feel so good."

  
She couldn't help but smile when she felt him pepper her cheek with soft kisses even as he relentlessly continued to thrust deep into her, Leonidas biting his lip as he focused solely on Mash's pleasure, and he was surely doing an incredible job. The Demi-Servant lay on her Master's chest, sharing several passionate, sloppy kisses while the pair continued on. Faster, harder, his hips bucked upwards each time Leonidas pulled away, pushing deeper and deeper inside of her.

  
"Mash, I think I'm going to-" He was cut off by a kiss, and her husky, lustful reply,

  
"I don't care, it's okay. Both of you, go ahead,"

  
He tried to last as long as he could, even with her moans, the wanting tone in which her words were spoken and the lustful, almost insatiable look in her eye. Faster, deeper, he moaned. Lightly at first, but they grew louder as he felt himself getting closer and closer to that final release. Sweat rolled down his forehead, down her back, down Leonidas' chest as the three put everything they had into this final act.

  
With a grunt and a moan, Leonidas released for a second time as she moaned in surprise, feeling his seed spreading inside of her, dripping out of her. "Come on, Senpai," Mash's voice was sweet yet desperate, encouraging him, "Cum inside of me,_ please._"

  
He gave a final moan in the middle of a messy kiss as his eyes closed, almost burning as he shot his cum deep inside of her womb. Even Mash was surprised, moaning louder as his sudden release triggered another orgasm, feeling his seed spreading inside of her. Gently, Lancer pulled out of her and took his leave after being reassured it was okay to do so.  
The pair left alone, he was left to look upon her current state; on her back, a smile on her face despite her cheeks a deep red, her chest rising and falling as she calmed down from the sheer magnitude of what just transpired. Most of all, he couldn't help but smirk seeing her pussy and ass dripping with cum.

  
"Senpai," She spoke up.

  
"Yes?" Was his reply, readying a wet towel to clean her up with,

  
"....I'm tired, but...that was enjoyable."

  
"Good." After cleaning her up, the pair shared a lazy, loving kiss before finally settling down to sleep, sufficiently worn out.

**Author's Note:**

> So this idea has been floating around in my head for a while and I finally got around to writing it so I hope it was enjoyable.
> 
> As a side note, they might have tricked everyone else, but DaVinci knows they're fucking. She's not stupid.


End file.
